This invention relates to tufting machines and more particularly to a needle plate finger mounting comb for mounting readily removable base material support fingers in a tufting machine.
In conventional tufting machines an oscillating looper or hook cooperates with a reciprocating needle to form loops at the reverse side of the backing material penetrated by the needle. The backing material is supported by fingers extending forwardly from a needle plate and the needles pass between the fingers. Until recently it has been common practice to secure the fingers into a slotted elongated needle plate which in turn was secured to the tufting machine bed plate, the fingers being secured as by swaging into the slots in the needle plate as illustrated in U.S. Pat. Nos. 2,976,829 and 3,064,600. If a finger was broken or damaged so as to require replacement, the needle plate had to be removed from the machine and the broken finger had to be hammered or chiselled out of the needle plate. To permit removal of the needle plate, since the base material is supported thereon, a large section of base material had to be cut away thereby subsequently requiring substantial mending and increasing the risk that the tufted fabric produced would be classified as a "second."
Although a later development suffered from the same deficiency of requiring a large portion of base material to be cut to remove the fingers, the fingers were not swaged into the slots so that the time for replacing broken fingers was reduced. In this development the fingers were inserted into slots in a first plate which was fixed to the bed plate and a second plate was secured to the first plate by screws to hold the needles therein. The first and second plates were removed as a unit, screws holding the plates together were removed and the plates disassembled from each other. However, although the fingers could be readily changed at the machine station, when the plates were disassembled the fingers tended to merely fall out and most if not all had to be reassembled into the plates.
Subsequently, with the development of modular components by the assignee of the present invention, small modular finger assemblies were developed in which the fingers were fixedly molded into a small body member and the body members were attached to a base plate secured to the bed plate. Although small modular members can be used to thereby avoid cutting a substantial amount of base material to permit removal of a module from the base plate, the fingers are fixed in the module and can't be replaced near the machine. Another module is substituted and the old module is either discarded or remanufactured to replace the broken fingers.
Thus, although it is desirable to provide finger mounting constructions which permit changing a broken finger at or near the machine station and providing means which only require a slight cut in the base material to remove the broken fingers, until the present invention no such construction has been developed.